The dynamics of coral reef benthic and reef fish communities in Batam and Natuna Islands, Indonesia

摘要

The dynamics of coral reef benthic and fish communities and their relationship within the Batam and Natuna Islands were investigated in 2004, 2007, 2010 and 2013. Hard coral covers declined at both locations (Batam by 18.69% and Natuna by 16.50%) in 2013, after which a mass bleaching event occurred in 2010. This dramatically affected fish abundance, given that there was a decline of 39.18 individuals per transect in Batam but strangely there was an increase by 47.36 individuals per transect for Natuna. This increase might be related to the isolated location of Natuna, which prevented fishes from migration, especially juveniles. In the same year, the benthic compositions in both locations changed from Acroporidae dominated reefs to become less complex reefs. Following this, the fish composition became less diverse for Batam but in reverse for Natuna. The changes in benthic communities correlate significantly with fish functional group diversity for Batam and the abundance for Natuna. These differences might be related to geographical conditions and human impacts which are different between the locations, such as being surrounded by group of islands or open sea, and fishing activities. The communities are dynamic spatially and temporally as a result of natural conditions of the environment and human activities.